To Intrepid Wheelwoman sorry to hear that about someone treating your daughter in such a way. Dave31 dogs are nice, I don't have one but when I go windsurf like today my friend brings his dog and walks him around before and after we sail. As my mom said after my dad died, "that's life". Good memories I bet you have from exercising the dogs that way while having fun yourself.
The LiPo (Lithium Polymer) battery used on most these helicopters I don't know if there any better now. The number of times you can recharge before it won't take a full charge again is key in how I feel about them. Also 8 minutes is not a long run time. There was a warning that you should not run the battery too far down. If you do discharge too much then it when recharged starts to puff up.
I think hydrogen gas or something not good. They will not be able to take a full charge as a result of discharging too far down. The only way to accurately know is to land it an measure the voltage on the battery. If at a point it take more throttle to lift off than when you started, it probably is time to stop and swap a recharged extra battery in place and immediately recharge the one taken out.
Throwing out the battery I know has problems environmentally, so I guess it should be taken to a hazardous waste / recycle place as there are in most cities. I have also heard to make the puffed up battery more safe to dispose is to discharge is slowly by putting it in a bucket of salt water and gravel. The gravel I think might be in case it decides to burst it won't fly outward.
https://sites.google.com/site/tjinguytech/charging-how-tos/lipo-disposal
Many more give information on making safe to dispose the battery when no longer able to use.
MT