I'm not sure it's necessarily the better way to go--it's been established that the only survivor has been hallucinating and it's hardly unreasonable for the characters to expect that.  On the other hand, Adams was not in the sickbay and while he was no doubt filled in on what happened it's not really the same as actually being there and watching Sonvek act in a way that is clearly out of touch with reality. So I can see that hallucinations aren't something that would occur him in the heat of the moment.<br/><br/>Of course, if it turns out invisible lizards actually are the culprits behind all this then our chief engineer will come out of this looking pretty sharp.  ;D