Aww thats awful
i remember when pearl escaped - luckily i stumbled out of bed for the loo (at night) and passed my mums room and heard a scuffling noise and was absolutely petrified - but she stuffed herself behind my mums drawers -.- took me and mum 2 hours to get her out!!
Is there a treat he likes? if so you could like shake it... just a thought...
try getting down to floor level and see where youd go if u were a hamster lol - works well actually
goodluck - hope u find him!