Sufyan: Does this happen every time you play the game? I've never had this particular problem but sometimes the scripting just breaks randomly. One problem I've had a handful times over the years is that Jack just stands around when he should tell you to enter the chop shop right after the shooting starts. The bum not spawning however is not something I remember.
lordhoff: This is no help but, I don't think you have to bite the bum; Jack says something like, "couldn't do it, eh?".
This is only the case for the rats which he asks you to feed from directly after having the bum as a snack. You can either do it and eat some rats or just talk to him again, which basically means you refuse.
I haven't heard of the bum disappearing and in the dozens of times I've played the tutorial it never happened to me; it might be a one-time glitch like your fists not appearing at the start of the tutorial. Since you're not far into the game yet, maybe you should try starting a new game and seeing if the problem persists. One-time glitches occasionally happen in Bloodlines.
