I believe that Tom is safer in Bangkok than certain parts of LA, Detroit, Philadelphia, Miami, Washington DC ...... Phoenix, Chicago and any metro area over 1 million people in the US. Bangkok, like all cities, has both good and bad neighborhoods. Also, like US cities, Bangkok is vulnerable to individuals or small groups that want to terrorize the population. Washington DC had its sniper. Phoenix had a serial rapist/murderer just this year. New York City had airplanes running into buildings. The residents stayed put.

No place is 100% safe. Bombs going off and hurting people is a scary thing. But I would not encourage Tom to leave Bangkok because of it -- that is what they want and there is no guarantee he is any safer on this side of the Pacific.