Gastroenterology
Gastroenterology
[The first five panels appear in a single row.] [Ponytail, wearing a lab coat, and a guy wearing a scrubs hat rush in from the right side of the panel. Ponytail is holding a water bottle. There is a desk on the left of the panel with two jars.] Hat guy: Hurry, they're right behind us!
[Zoom in on Ponytail, behind the desk, pouring the two smaller jars into the water bottle.] An arrow points to the left jar: Probiotic An arrow points to the right jar: Antibiotic
[A borderless panel. Zoom out on Ponytail shaking the water bottle to mix the two substances.] Shake Shake Shake
[Ponytail throws the water bottle toward the right side of the panel, at something off-screen.]
[Hat guy and Ponytail run toward the left side of the panel, as the water bottle explodes.] BOOM
[The last panel is the only panel in its row, appearing at the far right end of the row and slightly narrower than the fifth panel above it.] [Megan and Ponytail sitting at a table, facing each other, having a meal.] Megan: So what's gastroenterology like? Ponytail: Pretty boring. Lotta paperwork.

Gastroenterology is the study of the normal function and diseases of the digestive system: esophagus, stomach, small intestine, colon and rectum, pancreas, gallbladder, bile ducts and liver.
Antibiotics are substances that kill bacteria. They are effective at treating bacterial infections, including in the gut; unfortunately, they can also kill the normal gut bacteria. Probiotics are harmless or helpful bacteria which are sometimes used to replace the bacteria killed by an antibiotic. This reduces chances of re-infection by pathogens, and allows the natural gut microbiome to recover more effectively; comic 1471 was about the same theme. Probiotics are included in many foods, such as yogurt, as well as supplements, and are marketed as having health benefits.
The comic plays on the names probiotic and antibiotic.  When matter and antimatter are mixed, they annihilate each-other, rapidly releasing energy (an explosion).
This comic imagines a similar process when probiotics and antibiotics are mixed: Ponytail and a nurse runs into a room, with someone chasing after them, leading the nurse to exclaim that “they’re right behind us.” Ponytail mixes the probiotics and antibiotics, and throws the jar like a grenade, before continuing to run with the nurse. The reaction between the probiotics and antibiotics causes the jar to explode, presumably killing the pursuer. In reality, antibiotics and probiotics are often used simultaneously during treatment, but they are taken so that they do not mix (taken at different times or by different methods). Mixing them as in the comic, would just cause the antibiotic to kill the probiotic bacteria. Explosive reactions between antibiotics and probiotics are highly unlikely. [ citation needed ]
Matter and antimatter would react pretty much instantly upon mixing, not a short time later, as in the comic.  (Also, one could not keep antimatter in a normal jar, or pour it in an atmosphere).  The reaction shown is similar to the reaction between a strong acid and a strong base, which could cause an explosion after a short delay if kept in a tightly sealed container like a water bottle, as in the explosion here.
In the last panel, Ponytail is giving a more mundane summary of what gastroenterology is like (lots of paperwork). This is similar to Indiana Jones saying that archaeology is boring. The explosion sequence might be:
In the title text, Ponytail adds that her work makes her aware of a child coughing as the server was bringing food at the restaurant table, exposing the food to possible germs that could cause a gastrointestinal infection.
[The first five panels appear in a single row.] [Ponytail, wearing a lab coat, and a guy wearing a scrubs hat rush in from the right side of the panel. Ponytail is holding a water bottle. There is a desk on the left of the panel with two jars.] Hat guy: Hurry, they're right behind us!
[Zoom in on Ponytail, behind the desk, pouring the two smaller jars into the water bottle.] An arrow points to the left jar: Probiotic An arrow points to the right jar: Antibiotic
[A borderless panel. Zoom out on Ponytail shaking the water bottle to mix the two substances.] Shake Shake Shake
[Ponytail throws the water bottle toward the right side of the panel, at something off-screen.]
[Hat guy and Ponytail run toward the left side of the panel, as the water bottle explodes.] BOOM
[The last panel is the only panel in its row, appearing at the far right end of the row and slightly narrower than the fifth panel above it.] [Megan and Ponytail sitting at a table, facing each other, having a meal.] Megan: So what's gastroenterology like? Ponytail: Pretty boring. Lotta paperwork.
