Bread yeast starts easily and brews reasonably quickly. It may not have as high an alcohol tolerance as some yeasts, but it does plenty well enough for me. A fermentation lock is a device that allows the gas to escape but doesn't allow fresh air into the fermentation container. This is very important because fermentation is an anaerobic reaction which produces alcohol and biologically is referred to as anaerobic respiration. The second possible pathway for the respiration is aerobic respiration, which requires oxygen, and this breaks the alcohol down and also can make acetic acid, which is the stuff that makes vinegar sour.
Fermentation locks are cheap and available from any brewing supply shop.
I strongly suggest finding a real fermentation lock. Now that the mead is fermenting you need to monitor its progress. Put it in a safe warm place and check it a couple of times a day. Swirl the jug a few times each day to keep the yeast from settling too much and help release the carbon dioxide gas and that will help it ferment and also keep the foam down to a managable level. This can be a problem because of citrus pulp or other fruit pulp which gets lifted into the fermentation lock by the foaming head in the jug.