Seems to me that it would be your teammate's job to fight to keep your wheel once he's on and you're leading him out. I'll bet someone just took your wheel away from him. That wouldn't be your fault unless you did something erratic to cause him to slip off.

I think it would be a good idea to have a "debriefing" session with him and ask him what exactly happened, and how it happened, and then brainstorm how to keep it from happening again.

Bob

[edit: Just read your "he" post. Guess "I" just got schooled! LOL. But I still think a debriefing session would be helpful. You guys could come up with a code for "take me up to the front".]