To hide from the doctor, you can do one of two things. One is to use a disguise, which you can only do in specific places. The other is to run two tiles away from the range of his flashlight. Do note that losing means starting over from the beginning. This will affect the strategies you choose for later levels.

At the earliest levels, you’d want to favor an aggressive tactic. Collect more posters than the night demands to gain a huge high score early. In later, harder levels, you must pace yourself better. Choose a conservative play style that favors meeting rather than surpassing the quota.