His surprise attack actually works better than he'd planned; his blade finds a hom not just in the creature's back, but apparently shredding some vital organ, as it doesn't even twitch, merely goes limp, as soon as he hits it. With that target no longer a risk, he can direct his ray at the uninjured spider, searing directly through its abdomen, severing the creature in half, leaving only the badly wounded spider left to face him.<br/><br/>(Initiative to beat the spider... which nat 1's, so you're going first. If you miss AC 14, it'll attack at 17 vs. AC, for 3 damage plus a DC 14 fort save.)