So you moved from primary into a secondary? Lagering takes times so I don't think you will have any issues with bottle bombs as long as you wait the appropriate amount of time before you bottle. Active yeast during secondary happens either because you transferred too early, or you roused the yeast a little causing them to become somewhat active again. Bringing up the temp can do this as well. Just as long as you don't bottle in serving bottles during this activity you should be fine. Now that it is in secondary give it plenty of time.
“Alcohol may be man's worst enemy, but the bible says love your enemy.”- Frank Sinatra
“I feel sorry for people who don't drink. When they wake up in the morning, that's as good as they're going to feel all day.”- Frank Sinatra
Reason: Oh yeah