Yes, an umbrella can be used in the same way as an Arnis stick during an emergency as both are used for self-defense purposes. It is possible to practice techniques with an umbrella in the absence of an Arnis stick as the principles of self-defense remain the same regardless of the tool used. However, it is important to note that an Arnis stick is specifically designed and weighted for self-defense techniques, while an umbrella may not be as effective or safe