The microwave energy used, is frequency controlled and not likely in the range that would affect a pacemaker.
Secondly, I also doubt that someone with a pacemaker would be participating in a riot.
Thirdly, if pacemakers were affected, they would be dropping like fies now, as microwave energy is used extensively in the US and other western countries for communications. The towers are everywhere.
Looks to me like this thing is much safer than anything we currently use for crowd control. They are only looking to get some water molecules vibrating and creating a bit of heat. The range is a few hundred feet and the danger is no more than that of a MRI machine. Probably much less.